Low heat leak structural support



March 1963 R. P. JAMES 3,080,086

LOW HEAT LEAK STRUCTURAL SUPPORT Filed May 27, 1960 INVENTOR.

ROBERT P JAMES BY United States Patent 3,030,986 LSW HEAT LEAKSTRUCTURAL SUPPORT Robert P. denies, San Marino, Calif, assignor toLockheed Aircraft Corporation, Burbank, Calif. Filed May 27, 1960, Ser.No. 32,265 1 Claim. (Cl. 220-) This invention pertains to a containerfor fluids having a temperature greatly different from the ambienttemper-ature. More particularly, it pertains to low heat leak supportmeans for a container of liquids having extreme temperatures.

Where it is necessary to contain a liquid of either a very high or verylow temperature, it becomes imperative to minimize heat transfer betweenthe liquid and the surrounding areas. This is particularly true where acryogenic fuel having a temperature in the range of 400 degrees belowzero Fahrenheit is used in a high speed aircraft which will be subjectedto external temperatures in the range of 400 degrees above zero. This800 degree temperature dilference is compounded where space ]imits thephysical size of any insulating materials carried in the craft.

Many good insulating materials are available but none are sufficientlystrong to support the weight of the container and the liquid therein.Other materials have sufficient strength to support the weight of thecontainer and the liquid but have relatively poor insulating properties.Among these structurally strong materials some have a high heat transferco-eflicient and others a low heat transfer co-etdcient. By selectingmaterials from the group having a low heat transfer co-efiicient andconstructing support structure such that any heat transfer would have totravel a long path there will be a minimum heat transfer.

It is an object of this invention to provide a container (and supportmeans therefor to contain a liquid having extreme temperatures. It isanother object of this invention to provide a container and supportmeans therefore for a liquid having an extreme temperature which willprovide for minimum heat transfer between the liquid and exterior of thecontainer. It is another object of the present invention to provide asupport means for a container which has strong structural features,takes up minimum space and has a long heat leak path. It is anotherobject of the present invention to provide a support for a containercontaining liquids having extreme temperatures which is comprised ofmaterials having a low heat transfer co-efficient and which has a longheat leak path. It is another object of this invention to provide astructural support for a container having great strength, light weight,a low heat transfer co-etncient and a long heat leak path to provide aninsulation between the interior and the exterior of the container.

Further advantages and objects of the invention will become apparentfrom a reading of the following specification especially when taken inconjunction with the appended drawing wherein like numerals indicatelike elements.

IGURE 1 is a cross sectional View of the support showing the containerand exterior framework;

FIGURE 2 is a view taken on lines 2-2 of FIGURE 1.

A vacuum is one of the better known insulators. However, even though avacuum is used for insulation purposes, if the container or area beinginsulated has any weight, other means must be provided to support thatweight. Other materials such as foamed plastic do have property forsupporting a small weight but will not provide sufiicient support for aheavy liquid. Some material of sufficient strength to support anappreciable weight must be used. Among those materials having sufficientstrength are those which have a low co-efficient of heat transfer. Oneof the better materials for this purpose from a point of view of cost,availability, and ease of use, is stainless steel. However stainlesssteel by itself does not provide a sufficient insulation between hot andcold areas to minimize heat transfer. This heat transfer can beminimized by providing a support having a long heat leak path from onetemperature extreme to the other and being comprised of the materialhaving a low heat transfer co-eificient. This invention provides theoptimum combination of a structurally strong support comprised of amaterial having a low co-efiicient of heat transfer and used in such amanner that a long heat leal: path is provided in a small space and sothat additional insulating materials may be used.

The container 10 is spaced inwardly from an outer shell 11 which couldbe any supporting framework. An intermediate wall 12 is shown toexemplify the versatility of this invention. Wall 12 may partition areas15 and 16 in which there may be a vacuum or various insulating materialssuch as gases having increasing boiling temperatures where a cryogenicliquid is carried in container 14) or gases having decreasing boilingtemperatures in case the liquid in container 1% is of a highertemperature than the ambient outside of the supporting shell 11. Anelongated structural beam 20 extends from the exterior shell 11 to theinterior of container It}. A primary support is provided at the pointthat beam 20 passes through the wall of container 1% comprised an innerbearing race 22 fixed to beam 29 and an outer bearing race 24 fixed tothe wall of container 19 with ball bearings 25 therebetween to providefor minimum contact between the beam 26 and the wall structure ofcontainer 10. This minimum contact provides for minimum heat transferfrom the beam 2% to the wall 10 of the container and its contents orvice versa. The fewer the number of balls 25, the less the contact area.

Surrounding the inner part of beam 20 is a layer of foamed plastic 23 orother insulating material contained in shell 29 to aid in insulatingbeam 26 from the interior of container 18. The space 30 on the interiorof beam 29 may also be evacuated or filled with an insulating material.The inner end of beam 20 is attached to cone member 32 through the usualthreaded structure on the interior of cap 33. Beam 29 is taperedinwardly to facilitate removal through opening 34 in the shell 11 whichis closed by cap 35.

The cone member 32 is spaced from member 2d and its surroundinginsulation so that the only substantial heat transfer contact thatmember 2% has with the liquid inside container 10 is through the cap 33.The base of cone member 32 is fixed in a fluid tight relationship to theinterior walls of container 10 in a circular area spaced radially fromthe ball bearing primary support 25 so as to isolate the point ofcontact at cap 33 and beam 20. Cone 32 is shown reinforced by member 38on its interior surface. The distance from balls 25 through race 24along wall 36 provides an additional long heat leak path from beam 20 tothe walls of container 16.

The structure shown and described has been found effective to insulatevery cold fluids from extreme heat such as would be found in a spacevehicle where liquid gases are used as fuel at temperatures somewherebelow 400 F. in environments which would raise the tempera: ture ofshell 11 to Well above 400 F. I wish not to be restricted to thespecific details shown in the appended drawings but claim as myinvention the combinations and their equivalents as set out in theappended claim.

I claim:

Means to contain liquids comprised of an outer shell, an inner containerof a smaller exterior dimension than the outer shell and spaceduniior-mly inwardlyirom the outer shell, an elongated conical beamcomprised of a low heat transfer material having a fastening means onits outer end mating with like fastening means "on the outer shell andextending perpendieularlythrcugh the wall of the inner container intoits interior a substantial distance, a bearing race about the conicalbeam where it passes through the wall of the inner container, "a bearingrace fixed to the wall of the inner container about the conical beam,ball bearings comprised of low heat trans- 10 :Ee'r material between theraces, a cone member comprised of a low heat transfer materialhaving'i-ts apex threaded to the inner end of the elongated conical beamand its base fixed to the interior wall of the inner container in afluid type relationship.

References Cited in the file of this patent UNITED STATES PATENTSPreston Nov. 7, 1950 Ian. 3,

